Multi-phase synthetic ripple power converter

摘要

A novel method to operate synthetic ripple multi-phase switching power converters at constant frequency is presented. The method includes the means for sensing the current in each phase without adding extra dissipation and for balancing the currents by affecting the synthetic ripple signal to modulate the duty cycle without disturbing the overall output voltage regulation. Furthermore a method for obtaining optimum load transient response is presented. The method includes the means for simply determining the derivative of the synthetic ripple signal and for forcing maximum duty cycle until the derivative of the synthetic ripple signal reaches a certain threshold. A variant of this method improves further the load transient response by coupling an RC network to the ramp signal generated to modulate the duty cycle so as to maintain the maximum duty cycle a bit longer after the derivative of the synthetic ripple signal has reached the zero value.